A British gem - The English Oak

English Oak is arguably the most distinguishable and beloved of all native British trees. I don't believe I know anyone who cannot identify an oak tree. It is indeed the most common tree species in the UK, and it makes up a large percentage of British deciduous woodland. It also has an important wildlife and ecological value, in addition to the historical importance of oak trees in shipbuilding and its royal associations.

The common name may be English Oak, but it is better known as Quercus robur in the scientific community, and it is taxonomically placed in the Family Fagaceae.

The English oak can grow up to 40m tall, and in England, this tree has become a national emblem. You may also recognise the National Trust's and Woodland Trust's logos; they are of the leaf of an oak tree. A mature English Oak will have a broad crown of leaves, which grow to around 10cm in length with 4-5 lobes cut into the sides with smooth edges. The leaves generally emerge from their buds in May, and they have short leaf stalk (petioles), and grow in clusters. There is considerable branching beneath the canopy, as the image below illustrates. I took this image on the 17th November 2016, by the UEA lake. As you can see, the leaves had begun to turn an orange/brown colour, which for many of us marks the autumn season. The process by which the trees lose their leaves is known as abscission, which documents the natural detachment of plant parts, most commonly dead leaves, as seen at the turn of the seasons. This characteristic is what classifies trees such as the English Oak as deciduous; "deciduous" means "falling off at maturity" or "once its purpose is finished".

Oak trees produce a fruiting body, known as the acorn. Acorns can grow up to 2.5cm long, and are borne on lengthy stalks in English Oak, and they are held tightly by cupules (this is the cup-shaped base of the acorn). Acorns fall from the canopy in the autumn, and a new sapling will appear the following spring given successful germination. Not all acorns will germinate successfully however, as they are a vital food source for many species, including but not limited to, jays, mice, rats, squirrels and many other birds.

Oak trees have a silvery brown bark, which over time becomes rugged and begins to look cracked. The fissures in the oak trees' bark increase with age. The image below illustrates an oak tree's fissured bark, and this photo was taken of an oak tree by the UEA lake. Oak trees can live up to 1000 years of age, but most will survive for approximately 500-600 years, reaching maturity at around 80 years old. 

Mythology:

• The oak tree was sacred to the Greek God Zeus, the Roman God Jupiter and the Celtic God Dagda. Each of these was a God of Thunder/lightening, and as oak trees are prone to lightening strikes due to their height, these trees came to be a sacred emblem.
• Oak groves provided shelter and sanctuary for the druids to practice their rituals. Druids also favoured mistletoe, and this is a common parasitic plant found in oak branches.
• Royalty has a historic association with oak trees, as English kings would wear crowns of oak leaves, and notably King Charles II was found hiding in an oak tree at Boscobel House from his pursuers.